Apparatus for routing signals

ABSTRACT

An apparatus for routing signals to and from at least one circuit component that has a plurality of input/output leads includes a support structure having a first side and a second side. The first side is adapted to have the input/output leads of the circuit component attached thereto. A signal routing strip having a first end and a second end is also included. The first end of the routing strip is configured and adapted to be electrically connected to the input/output leads of the circuit component for transmitting signals to and from the circuit component.

BACKGROUND

[0001] The present invention generally relates to apparatus for routingsignals to and from circuit components, and more particularly toapparatus for reducing signal routing complexity and congestion, andincreasing signal routing flexibility.

[0002] The use of various integrated chips (ICs) having leads orcontacts which protrude from the bottom or the sides of the packages andadapted to be positioned on a printed circuit board (PCB) is commonlyknown. Typically, signals to and from components on the PCB aretransmitted through signal paths formed in the PCB. These paths aregenerally electrically conductive traces which have a relatively finewidth and imbedded in the multiple layers of the PCB to accommodatenumerous signals. This known method of routing signals may be adequatefor purposes of routing signals between a relatively small number ofcircuit components. However, it is not suitable when a large number ofcomponents, and a correspondingly large number of signal paths betweenthem, are required. The increase in the number of circuit components onthe PCB significantly increases the complexity of the signal paths onthe PCB, resulting in higher manufacturing costs. Expanding the size ofthe PCB to accommodate the increased number of circuit components couldlead to stress fracturing of the delicate signal traces. Also, the knownmethod of signal routing is specific to a particular circuit componentconfiguration. Consequently, a PCB configured for one purpose generallywould not be suitable for different applications.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003]FIG. 1 is a simplified perspective view of a signal routingapparatus in accordance with one embodiment of the present invention;

[0004]FIG. 2 is a perspective view of a routing strip shown in FIG. 1;

[0005]FIG. 2A is an enlarged side view of encircled section 2A of therouting strip of FIG. 2;

[0006]FIG. 3 is a perspective view of another embodiment of a signalrouting apparatus according to the present invention;

[0007]FIG. 4 is a perspective view of an integrated circuit (IC) inaccordance with the invention;

[0008]FIG. 4A is an enlarged view of a section of FIG. 4, illustratingthe connection between a die and a package of the IC;

[0009]FIG. 4B is an enlarged view of section 4B of FIG. 4, illustratingan alternative method of making the connection between the die and thepackage.

[0010]FIG. 5 is a simplified side view showing the integrated circuit(IC) of FIG. 4 attached to a printed circuit board and a routing strip;and,

[0011]FIG. 6 is a perspective view illustrating the manner in which acircuit component is attached to the IC of FIG. 4.

DETAILED DESCRIPTION

[0012] Broadly stated, the present invention is directed to an apparatusfor routing signals to and from at least one circuit component that hasa plurality of input/output leads. The apparatus includes a supportstructure having a first side and a second side. The first side isadapted to have the input/output leads of the circuit component attachedthereto. A signal routing strip having a first end and a second end isalso included. The first end of the routing strip is configured andadapted to be electrically connected to the input/output leads of thecircuit component for transmitting signals to and from the circuitcomponent.

[0013] The present device for routing signals to and from a plurality ofinput/output leads on a circuit component includes a strip having afirst side and a second side, and a first end and a second end. Aplurality of electrically conductive traces are imbedded in the stripbetween the first side and the second side. A plurality of electricalterminals extend from the conductive traces and protrude from the stripat the first end and the second end on at least the first side. Theterminals at the first end of the strip are configured and adapted to beconnected to the input/output leads on a first circuit component toenable signals to be transmitted to and from the first circuit componentfrom and to the terminals at the second end of the strip.

[0014] The present invention also relates to an integrated circuitdevice including a die for performing the functions of the integratedcircuit device. The die has a plurality of input/output terminals. Alsoincluded is a package which is configured and adapted to receive thedie, and has a top surface and a bottom surface. A plurality of externalconnection leads are formed on the top surface and the bottom surface ofthe package, and connected to the input/output terminals of the die.

[0015] The external connection leads on the top surface are configuredand adapted to be attached to corresponding input and output leads of acircuit component placed over the top surface of the package, so thatthe circuit component can be stacked directly on the top of theintegrated circuit device. Turning now to FIG. 1, the signal routingapparatus of one embodiment of the present invention is indicatedgenerally at 10 and includes a support structure 12, preferably aprinted circuit board (PCB), a plurality of circuit components 14 (twoshown), and at least one routing strip 16. The support structure 12 isconstructed from known material used for fabricating PCBs, such asfiberglass, for example, and includes a plurality of electrical and/ormechanical interfaces or land patterns 18 (two shown). Each land pattern18 is made of a plurality of electrically conductive holes or vias 20which extend partially or completely through the support structure 12.The circuit components 14, such as integrated circuits (ICs), areadapted to be positioned over the land patterns 18 So that theinput/output leads of the circuit components (shown in FIG. 2 as 44)make electrical contact with the vias 20. Accordingly, the vias 20 arearranged to match at least the pattern of the electrical input/outputleads 44 of a corresponding circuit component 14. Preferably, each landpattern 18 includes a sufficient number of vias 20 to accommodate thedifferent input and output configurations patterns of various circuitcomponents 14. The routing strips 16 are adapted to transmit signals toand from the circuit components 14 on the support structure 12. Theytransmit various data signals, as well as power to the circuitcomponents 14, if required. The routing strips 16 may also have signallines for providing ground for the circuit components 14. At least twoend portions 22 are provided on each of the routing strips 16, with eachend portion having a plurality of electrical terminals 24. Theseterminals 24 are adapted to be connected to the land patterns 18 on theopposite side of the support structure 12 from the circuit components14. In this manner, the terminals 24 electrically connect to the circuitcomponents 14 through the vias 20, and signals to and from the circuitcomponents are transmitted by the routing strips 16. Accordingly, theterminals 24 at one end portion 22 are arranged to correspond to theinput/output lead configuration on the corresponding circuit component14. The terminals at the other end portion 22 are arranged to correspondto the input/output lead configuration of its corresponding circuitcomponent. In this manner, signals between the circuit components 14 atthe two end portions 22 are transmitted by the routing strip 16. Thepreferred manner of connecting the terminals 24 of the routing strip 16to the vias 20 is to attach solder balls to the terminals, align theterminals to the corresponding vias and heat in oven until the terminalsand the vias are soldered together.

[0016] Turning now to FIG. 2, the routing strip 16 is shown with the twoend portions 22 having the plurality of terminals 24 in a pattern 26. Itshould be noted that the outing strips 16 may have more than two endportions 22 to carry signals between increased number of circuitcomponents 14. In an embodiment shown in FIG. 2A, the routing strip 16includes a top insulating/shield layer 28, a first signal trace layer30, a power plane 32, a second signal trace layer 34, a ground plane 36and a bottom insulating/shield layer 38. The top and the bottominsulating/shield layers 28, 38 insulate the routing strips 16 when theyare attached directly to the support structure 12 on which the circuitcomponents 14 are provided, and/or acts as a shield when high frequencysignals are being transmitted by the routing strips. The first and thesecond signal trace layers 30, 34 have electrically conductive wires ortraces 31 imbedded therein for carrying signals to and from the circuitcomponents 14. These traces begin and end at the terminals 24 on the endportions 22 of the routing strip 16. Power, if required, is supplied tothe circuit components 14 by electrically conductive traces or wires 33embedded in the power plane 32. The ground plane 36 provides anelectrical path in the form of a wire or trace 35 through which thecircuit components 14 on the support structure 12 are grounded.

[0017] It should be understood that the routing strip 16 described abovedepicts only one embodiment, and that it can have alternativearrangements. For example, the routing strip 16 may or may not includethe power plane 32 or the ground plane 36, depending on the type ofcircuit components 14 to which the routing strip 16 is designed to beconnected. Also, depending on the number of signals that the routingstrip 16 is designed to carry, it may have one or more signal tracelayers 30. Further, the routing strip 16 may be constructed from a rigidmaterial such as fiberglass, for example, or from a flexible plasticmaterial.

[0018] In accordance with another embodiment of the present invention,and referring still to FIG. 2, the routing strip 16 is provided with theterminals 24 on a bottom side 40 of the routing strip, in addition tothose on a top side 42. The terminals 24 on the bottom side 40 allow thecircuit components 14 to be attached directly to the routing strip 16itself, in addition to the support structure 12, thereby furtherreducing complexity and congestion on the support structure 12. As withthe terminals 24 on the top side 42 of the routing strip 16, the bottomside terminals 24 are arranged in a pattern to correspond at least tothe input/output leads 44 of the corresponding circuit component 14.

[0019] As a variation of this embodiment, it is contemplated that allthe circuit components 14 be attached directly to the routing strips 16,thereby eliminating the necessity of the support structure 12, such as aPCB, altogether. The routing strips 16 can then be attached to theplastic, metal or other surfaces of the intended product housing thecircuit components 14.

[0020] Turning now to FIG. 3, and in accordance with another aspect ofthe present invention, the routing strip 16 is attached to the supportstructure 12 on the same side as the circuit components 14. In thisembodiment, the routing strip 16 is attached to the top surface 42 ofthe support structure 12 and the input/output leads of the circuitcomponents 14 are attached to the terminals 24 of the routing strip.This arrangement eliminates the necessity of creating vias 20 (shown inFIG. 1) on the support structure 12, which results in further reductionin manufacturing costs.

[0021] Referring to FIGS. 4 and 4A-4B, one embodiment of an integratedcircuit (IC) 46 in accordance with the invention includes input/outputleads 48 formed both on its top surface 50 and a bottom surface 52. Asin conventional ICs, the input/output leads 48 on the bottom surface 52of the present IC 46 transmit signals to and from a die 54, the portionof the IC that performs the designed functions. In addition, the IC 46of the present invention is adapted to also transmit signals to and fromthe die 54 through its input/output leads 48 on the top surface 50.

[0022] More specifically, the die 54 is seated in a depression or well56 (best shown in FIGS. 4A and 4B) of a package 55. The package 55houses the die 54 and also provides the surfaces 50, 52 from which theinput/output leads 48 are allowed to protrude. In accordance with oneembodiment of the invention as shown in FIG. 4A, the die 54 is providedwith a plurality of input/output terminals 57 on its bottom surface thatfaces the floor of the well 56. The input/output terminals 57 may besolder balls which when heated bond to the package 55 on the floor ofthe well 56. The input/output terminals 57 are arranged such that theymake electrical connections with the ends of electrical conductors 58imbedded in the package 55. Each of the electrical conductors 58 haveone end which is exposed on the floor of the well 56 and the other endconnected to the input/output leads 48 on the top 50 or the bottom 52surfaces of the package 55. This arrangement allows the input/outputterminal 57 of the die 54 to be electrically connected to theinput/output lead 48 on the top 50 and the bottom 52 surfaces of thepackage 55 when the die is bonded to the floor of the well 56.

[0023]FIG. 4B shows another embodiment of the invention in which the die54 is adhered to floor of the well 56 in the package 55, but does nothave the input/output terminals 57 provided on its bottom surface.Rather, they are provided on the top surface 60 of the die 54. In thepreferred embodiment, the input/output terminals 57 are electricallyconductive pads disposed along the periphery of the die 54. However,other configurations and manners of forming the terminals 57 arecontemplated as dictated by design choice. The input/output terminals 57are connected to the corresponding input/output leads 48 on the top 50and the bottom 52 surfaces of the package 55 via connection points 62which are provided along the periphery 64 of the well 56. The connectionpoints 62 are electrically connected to the input/output terminals 57 bywires 66, and to the input/output leads 48 on the top 50 and the bottom52 surfaces of the package 55 through conductors 58 embedded in thepackage 55, thereby completing the signal paths from the die 54 to theinput/output leads 48 on the package.

[0024] The IC 46 of the present invention is particularly adapted to beused in conjunction with the above-described routing strip 16, as shownin FIG. 5. In FIG. 5, one end of the routing strip 16 is shown attachedto the input/output leads 48 on the top surface 50 of the IC 46, and theother end attached to the support structure 12, preferrably a PCB. Theinput/output leads 48 on the bottom surface 52 of the IC 46 are attachedto the support structure 12. This arrangement increases the signalrouting flexibility to and from the IC 46. For example, high frequency,path critical (length, impedance, etc.) signals might be routed throughthose connections between the support structure 12 and the IC 46, whileless path critical signals might be routed through the routing strip 16.

[0025] The input/output leads 48 on the top surface 50 of the package 55also allow the circuit component 14 to be mounted directly onto the IC46. An embodiment of this feature is illustrated in FIG. 6, which showsthe IC 46 having input/output leads 48 formed on the top surface 50 ofthe package 55 and on the bottom surface 52. The connections between theinput/output leads 48 and the die 54 are made in accordance with thedescriptions given above. The input/output leads 48 on the top surface50 form a land pattern 68 (i.e., a plurality of electrical interfaces),to allow the circuit component 14 to be attached directly onto the topsurface 50 of the IC 46. The circuit component 14 shown in the FIG. 6 isa conventional IC having the input/output leads 44 on its bottom surfacecorresponding to the input/output leads 48 of the land pattern 68. Theinput/output leads 44 of the circuit component 14 may be solder balls,for example, when heated and then cooled, are adapted to attachthemselves to their respective input/output leads 48 of the IC 46.

[0026] The input/output leads 48 on the bottom of the IC 46 are adaptedto be connected to a corresponding land pattern 18 on the supportstructure 12 such as a PCB (best shown in FIG. 1). Alternatively, the IC46, with or without the circuit component 14 attached, can be mounted onanother IC 46. In this arrangement, the input/output leads 48 on thebottom 50 of the first or top IC 46 would be arranged to make electricalconnection with their corresponding input/output leads 48 formed on thetop surface 52 of the second or bottom IC 46. The second or bottom IC 46may either be attached to the support structure 12 or to the top surface50 of yet another or third IC 46, thereby further reducing congestion onthe support structure 12 and increasing signal routing flexibility.

[0027] From the foregoing description, it can be seen that the variousembodiments of the present invention help reduce the complexity andcongestion on the signal carrying support structure by carrying signalson separate routing strips and/or stacking ICs directly on top of eachother. These arrangements contribute to prevention of stress fracturingof signal traces as the support structure becomes larger. The routingstrip also allows the support structure to be standardized by providingthe same land patterns on all the support structures and merely changingthe circuit components and the routing strips for differentapplications. The routing strip also enables ICs to have input/outputterminals on the top side of the package, thereby further increasingsignal routing flexibility.

[0028] While various embodiments of the present invention have beenshown and described, it should be understood that other modifications,substitutions and alternatives are apparent to one of ordinary skill inthe art. Such modifications, substitutions and alternatives can be madewithout departing from the spirit and scope of the invention, whichshould be determined from the appended claims.

What is claimed is:
 1. Apparatus for routing signals to and from aplurality of input/output leads on at least one circuit component, saidapparatus comprising: a strip having a first side and a second side, anda first end and a second end; a plurality of electrically conductivetraces imbedded in said strip between said first side and said secondside; and, a plurality of electrical terminals extending from saidconductive traces and protruding from said strip at said first end andsaid second end on at least said first side, wherein said terminals atsaid first end of said strip are configured and adapted to be connectedto the plurality of input/output leads on a first circuit component toroute signals to and from the first circuit component from and to saidterminals at said second end of said strip.
 2. The apparatus as definedin claim 1 wherein said terminals at said second end on said first sideof said strip is configured and adapted to be attached to theinput/output leads of a second circuit component.
 3. The apparatus asdefined in claim 1 wherein said strip is substantially flexible. 4.Apparatus for routing signals to and from at least one circuit componenthaving a plurality of input/output leads, said apparatus comprising: asupport structure having a first side and a second side, said first sidebeing adapted to have the input/output leads of the at least one circuitcomponent attached thereto; and, a signal routing strip having a firstend and a second end, said first end being configured and adapted to beelectrically connected to the input/output leads of the at least onecircuit component for transmitting signals to and from the circuitcomponent.
 5. The apparatus as defined in claim 4 further including aplurality of conductive patterns formed on said support structure andextending from said first side to said second side, wherein theinput/output leads of a first circuit component are adapted to beconnected to a corresponding conductive pattern at said first side ofsaid support structure.
 6. The apparatus as defined in claim 5 whereinsaid signal routing strip includes a first side and a second side and aplurality of electrical terminals formed on at least said first side atsaid first end and said second end, and said terminals on said first endof said first side are adapted to be connected to said conductivepattern that corresponds to the input/output leads of the first circuitcomponent at said second side of said support structure.
 7. Theapparatus as defined in claim 6 wherein a plurality of electricalterminals are provided on said second side of said signal routing stripat said first end and said second end, said terminals being configuredand adapted to have at least one circuit component attached thereto atat least one of said first end and said second end.
 8. The apparatus asdefined in claim 6 wherein said electrical terminals at said second endof said signal routing strip are attached to said support structure sothat signals can be transmitted between said support structure and thefirst circuit component.
 9. The apparatus as defined in claim 8 whereinsaid electrical terminals at said second end of said signal outing stripare configured and adapted to be attached to the input/output leads of asecond circuit component which is attached to said first side of saidsupport structure through a conductive pattern corresponding to theinput/output leads of the second circuit component.
 10. The apparatus asdefined in claim 4 wherein said second end of said routing strip isattached to said first side of said support structure so that saidsignals can be transmitted between said support structure and the firstcircuit component.
 11. The apparatus as defined in claim 4 wherein saidsecond end of said routing strip is attached to a second circuitcomponent on said first side of said support structure so that saidsignals can be transmitted between the second circuit component and thefirst circuit component.
 12. The apparatus as defined in claim 4 whereinsaid first end of said routing strip is adapted to be electricallyconnected to the input/output leads on a top of the first circuitcomponent, and the input/output leads on a bottom of the first circuitcomponent is adapted to be attached said support structure.
 13. Theapparatus as defined in claim 4 wherein said first end of said routingstrip is disposed between the input/output leads on a bottom of thefirst circuit component and said first side of said support structure.14. The apparatus as defined in claim 4, where said support structure isa printed circuit board (PCB).
 15. An integrated circuit devicecomprising: a die for performing functions of said integrated circuitdevice, and having a plurality of input/output terminals; a packageconfigured and adapted to receive said die, and having a first surfaceand a an opposing second surface; and, a plurality of externalconnection leads formed on said first surface and said second surface ofsaid package; wherein said input/output terminals of said die areelectrically connected to said external connection leads on said firstsurface and said top surface of said package.
 16. The apparatus asdefined in claim 15 wherein said package includes a depression and aplurality of attaching pads formed in said depression, and saidinput/output terminals of said die are formed on a bottom side of saiddie, and are configured and adapted to be attached to said attachingpads when said die is received in said depression.
 17. The apparatus asdefined in claim 16 wherein said attaching pads are electricallyconnected to said external connection leads on said first surface andsaid second surface of said package.
 18. The apparatus as defined inclaim 15 wherein said die includes a top side and a bottom side, saidinput/output terminals of said die are formed on said top side, and saidbottom side is attached to said package.
 19. The apparatus as defined inclaim 18 wherein said input/output terminals and said correspondingexternal connection leads are electrically connected to a plurality ofcorresponding connection points on said package.
 20. The apparatus asdefined in claim 15 wherein said external connection leads on saidsecond surface of said package are configured and adapted to beconnected to a printed circuit board.
 21. A stackable integrated circuitdevice adapted to have at least one circuit component attached thereto,said device comprising: a die for performing functions of saidintegrated circuit device, and having a plurality of input/outputterminals; a package configured and adapted to receive said die, andhaving a first surface and an opposing second surface; and, a pluralityof external connection leads formed on said first surface and saidsecond surface of said package, said external connection leads beingelectrically connected to said input/output terminals of said die;wherein said external connection leads on said first surface areconfigured and adapted to be connected to corresponding input and outputleads of the circuit component placed over said first surface of saidpackage.
 22. The device of claim 21 wherein said external connectionleads on said second surface of said package are configured and adaptedto be attached to a signal carrying support structure.
 23. The device ofclaim 21 wherein said external connection leads on said second surfaceof said package are configured and adapted to be connected to said firstsurface of said package of another said stackable integrated circuitdevice.
 24. The device of claim 21 wherein the circuit component is anintegrated circuit device having a plurality of input and output leadson a at least one surface thereof.